Iâ€™m not sure about this kind of CO2 injector - and never really have been, writes Nathan Hill. Iâ€™ve played with many rivals of similar design over the years and am yet to be impressed by them.

The idea is that you have a slow-release, solenoid-free, regulator-free simple way of adding carbon to the tank. You get a pressurised can of gas, which always feels empty courtesy of the density of CO2 inside, and a rather large chamber that sits inside the tank. Then at intervals you simply press the nozzle of the can and refill the chamber.

So, yes, it’s easy, but is it accurate? I’m wary that I can’t control the actual flow of CO2 going into the water and that fine adjustments over levels are non-existent. I’m also painfully aware that unstable levels of the gas can cause as much trouble as no CO2 in a planted aquarium where trying to control algae.

The advantage here is that you can keep the canister of gas in place outside the tank, connected up permanently with the supplied air line, via the supplied non-return valve, into the diffusing chamber. That at least negates the fiddly connecting-up required with some attempts of this design, as created by some companies.

It’s easy enough to use and there’s a handy dosing indicator on the packet, with Tropica rating this device for anything up to a 60l/13 gal tank. At that size, the 5,000 ml canister of gas will last around a month.

You need to vent the chamber periodically, so it’s not exactly maintenance free, but I guess if you’re on the fence about whether CO2 is for you, this is a cheap enough entry point at which to start experimenting.

Verdict

I’m not sure why Tropica needed this in its range, but I dare say that a host of aquarists will get good results and certainly value for money. It’s just not really for me, I think.